INTRODUCTION
Instability of the distal radioulnar joint (DRUJ) presents a major challenge to the wrist reconstructive surgeon. Chronic instability and arthritic changes at the DRUJ can lead to pain, decreased forearm rotation, diminished grip strength, and other functional limitations. The DRUJ derives its stability from soft tissues, particularly the triangular fibrocartilage complex (TFCC) rather than from the bony architecture of the distal ulna articulating in the shallow sigmoid notch of the radius.
Procedures for reconstructing these soft tissue attachments generally fall into one of two categories: extra-articular reconstructions or intra-articular reconstructions. Furthermore, extra-articular reconstructions can be categorized as either direct or indirect tethers. An example of a direct radioulnar tether that is extrinsic to the joint was described by Fulkerson and Watson, in which a free tendon graft is used to directly attach the radius and ulna. Indirect radioulnar links through a carpal sling or a tenodesis have been described, but these were salvage procedures post-Darrach, or they do not provide sufficient stability to the distal radioulnar joint.
In cases of severe DRUJ destruction, arthroplasty with ulnar head implants has been developed. The newer procedures of ulnar head and sigmoid replacement make it imperative to develop a reliable DRUJ stabilizing technique because local soft tissues are often insufficient for stability of the DRUJ.
This chapter describes a new technique that uses the brachioradialis (BR) tendon as a distally based tendon wrap around the distal ulna to hold it stable against the radius in a watch-strap fashion. The BR tendon is broad, flat, and long and is able to wrap around the reconstructed distal ulna, holding it reduced in the sigmoid notch. We believe that this reconstruction provides excellent soft tissue stabilization of the distal ulna, since the local soft tissues are never enough for full stabilization. It provides a very good alternative to much more aggressive DRUJ reconstructions using constrained implants in these challenging cases.
INDICATIONS AND CONTRAINDICATIONS
The BR wrap is applicable to the unstable DRUJ with preserved ulnar head as well as joints with prosthetic reconstruction of the ulnar head and/or the sigmoid notch.
Active infection forms the only contraindication for the BR wrap. Prior disinsertion of the BR tendon during previous distal radius internal fixation forms a relative contraindication to this procedure. Deficient skin over the ulna should be managed by resurfacing with a flap prior to the BR wrap.
SURGICAL TECHNIQUE
The BR tendon is harvested using a two-incision technique. First, a 4-cm incision is made over the radial aspect of the forearm, where the BR tendon is identified proximal to the first compartment. A second 4-cm incision is made more proximally at the musculotendinous junction of the BR, where the radial sensory nerve is dissected between the extensor carpi radialis longus and the BR ( Fig. 32-1 ). The muscle is gently teased off the tendon at the musculotendinous junction, thereby gaining maximum tendon length. After freeing the tendon of soft tissue attachments through both the proximal and the distal incisions while protecting the radial sensory nerve, the BR tendon is now withdrawn at the distal incision just proximal to the first dorsal compartment, where it is left inserted to the radial styloid (the first dorsal compartment is not opened) ( Figs. 32-2, 32-3, and 32-4 ).
